Plasma processing apparatuses are used to process substrates by techniques including etching, physical vapor deposition (PVD), chemical vapor deposition (CVD), ion implantation, and resist removal. One type of plasma processing apparatus used in plasma processing includes a reaction chamber containing upper and bottom electrodes. An electric field is established between the electrodes to excite a process gas into the plasma state to process substrates in the reaction chamber.
One type of upper electrode assembly used in plasma processing includes a showerhead electrode assembly. A showerhead electrode assembly of a plasma processing apparatus may include a thermal control plate attached to a showerhead electrode, and a top plate attached to the thermal control plate. At least one thermal bridge can be provided between opposed surfaces of the thermal control plate and the top plate to allow electrical and thermal conduction between the thermal control plate and top plate. A thermally and electrically conductive gasket may separate the top plate and the showerhead electrode, as described in commonly-owned U.S. Pat. No. 7,862,682, which is incorporated herein by reference in its entirety. A single zone or multi-zone film heater supported by the thermal control plate may cooperate with the temperature-controlled top plate to maintain the showerhead electrode at a desired temperature, as described in commonly-owned U.S. Pat. No. 7,645,341, which is incorporated herein by reference in its entirety.